d-magnetism instability in R-Co intermetallic compounds

Magnetic phenomena observed in R-Co intermetallic compounds with the d-magnetism instability are reviewed. The magnetic instability in these compounds is intimately related to the special position of the Fermi level in the hybridized 3d-5d (4d) band near to a local peak in N(ε). In the presence of the f-d exchange interaction the magnetic state of the itinerant electron subsystem can essentially be modified giving rise to a number of field- and temperature-induced magnetic phase transitions. Following the band structure calculations these transitions as well as most of their fine details can be well understood theoretically. Magnetic, magnetoelastic and transport measurements of some R-Co compounds with d-magnetism instability and pseudobinary systems with R and Co substituted by either magnetic or nonmagnetic elements are presented and discussed.